Mixed Signal Hardware Design Engineer

Apple

Given an integer array nums where every element appears three times except for one, which appears exactly once. Find the single element and return it. You must implement a solution with a linear runtime complexity and use only constant extra space. For example, if the input is nums = [2,2,3,2], the output should be 3. Another example, if the input is nums = [0,1,0,1,0,1,99], the output should be 99. How do you solve this problem, considering edge cases like empty input, presence of zero, and negative numbers?

Apple

You're troubleshooting a mission-critical server (cannot be rebooted) that is experiencing severe lag. You only have terminal access. Describe your debugging process, including specific commands and tools you'd use to diagnose the issue. For example, would you start by checking CPU usage, memory consumption, or disk I/O? What commands would you use to identify the most resource-intensive processes? How would you investigate potential network bottlenecks or file system issues? Be as detailed as possible in outlining your approach to pinpointing the cause of the lag and suggesting potential solutions, keeping in mind that a reboot is not an option.

Apple

Let's say a developer doesn't agree that a reported bug is actually a bug. How would you handle this situation? Be specific. For example, imagine you're a QA engineer, and you find that a button on a webpage is slightly misaligned in a specific browser. You log this as a bug, but the front-end developer says it's 'within acceptable tolerances' and refuses to fix it. Or, perhaps a back-end developer claims that a specific edge-case error is so rare it's not worth the effort to address, even though you believe it violates the product's stated reliability goals. What steps would you take to resolve the disagreement while maintaining a positive working relationship and ensuring product quality? Consider the different approaches you could take based on the severity and impact of the potential bug.